FIG. 1 shows a prior art operational amplifier output stage. The prior art circuit of FIG. 1 includes transistors M.sub.10 -M.sub.17, resistors R.sub.C1 and R.sub.C2, capacitors C.sub.C1 and C.sub.C2, negative rail V.sub.SS, positive rail V.sub.DD, input voltage V.sub.IN, output voltage V.sub.OUT, and bias voltages V.sub.B1 and V.sub.B2. When the input voltage V.sub.IN is close to the negative rail V.sub.SS, transistor M.sub.16 has the potential to source much more current than M.sub.17 sinks so the output voltage V.sub.OUT is close to the positive rail V.sub.DD. The gate of transistor M.sub.17 is then at a lower voltage than the drain. If there is a large positive voltage step at the input V.sub.IN of this stage, transistor M.sub.16 turns off quickly. However, to drive the output voltage close to the negative rail V.sub.SS, M.sub.17 must provide current to the load. Thus the voltage from gate to drain of M.sub.17 must change from a large negative value to a positive value. This change requires a large current to pass through C.sub.C1. The only source for this current is transistor M.sub.11. Due to a constant voltage at its gate, transistor M.sub.11 provides a constant bias current for M.sub.13 and M.sub.15, but this current is not sufficient to charge C.sub.C1 quickly enough for large signal transitions. Therefore this output stage exhibits crossover distortion under heavy loading conditions.